An upstate New York man who police say appeared to be fixated on Barbara Bush has been charged with threatening her father, former President George W. Bush, after he was found in Manhattan, heavily armed in his car, according to a federal criminal complaint.

Benjamin Smith allegedly yelled "Bush will get his," after he was arrested Friday in midtown Manhattan, where he was found in his car with a rifle, machete, gasoline and two boxes of ammonization, according to the complaint.

Law enforcement officials were alerted by Smith's mother on Thursday after she found what she said was a disturbing note at their shared home in Pittsburgh, N.Y.

"I'm going to work for George W. Bush and the pentagon," Smith allegedly wrote. "I have to slay a dragon and Barbara Bush is mine."

Smith's mother also told police that a rifle was missing from the house.

Secret Service agents were able to track Smith's cell phone to a Midtown street in Manhattan on Friday, where he was taken into custody around 6 a.m.

During questioning Smith appeared to be fixated on the daughter of George W. Bush, according to the complaint.

When he was asked about his marital status, he responded, "I am divorced and not currently seeing anyone but I am working on a relationship with Barbara Bush."

At a hearing Friday, Assistant U.S. Attorney Andrea Grisworld told U.S. Magistrate Judge Henry Pitman the government believes Smith was fixated on the daughter of the former president, according to the Reuters news service.

Smith's lawyer, Peggy Cross-Goldenberg, said the note and Smith's statements after his arrest did not lead to a "true threat," according to Reuters.

Cross-Goldenberg did not immediately respond to request for further comment from ABC News.

During the hearing Pitman reportedly said it was "unclear" whether Smith would be found guilty by a jury.

Barbara Bush lives in New York City, but the former president does not and was not in the city this week.